It's 8.20 pm, dark and raining in Melbourne John, but I'll take a photo of my centre dash arrangement tomorrow and post it. Years ago I found a brand new mini tape casette player in its original box and fitted it below the current AM/FM removable face radio/CD player that my son-in-law was throwing out because he couldn't recall/get past the lock out code built into it. Since then I've also included a couple of USB ports (Ebay) to run/charge any modern devices if I choose. Both have internal LEDs that glow when swithched on. There's a 3 way toggle switch beside the radio and cassette player that switches power from one to the other and another toggle that powers the USB ports. So there's no parasitic drain when the car is switched off!
From the above post here's 2 images of the radio/CD player with the USB and 12v ports switched off and active...as noted by the blue glow emanating from them. The outer surround to the Radio/CD player still requires a finishing cover (one of those small tasks that gets constantly put-aside by larger projects but needs to be done!)
Couldn't you connect the wiring in a way so that voltage is off when ignition is off?
Yes I could have Olaf...but what if I wanted to use whatever device I've connected to one of these ports with the ignition switched off! My coupe didn't come with an accessories position on the ignition switch. If you wire an accessory that way and don't have an accessory position on your car's ignition switch you could very easily cook the coil, burn the points or damage an electronic ignition module if the 'switch' or points are closed, as current is flowing through the ignition system. The blue light is a fairly obvious indicator that the devices are on.